Saikyou no Mamono ni Naru Michi wo Tadoru Ore, Isekaijuu de Zamaa wo Shikkou suru

After dying in a sudden accident in the modern world, the protagonist awakens to find himself reincarnated in a strange fantasy realm. However, he is no longer human; he has been reborn as a demon. Completely disoriented and unfamiliar with his new surroundings, he is quickly ambushed by a vicious monster. Barely managing to escape with his life intact, he is ultimately rescued by Charlotte, the daughter of a powerful duke. Charlotte proves to be a remarkably kind and innocent young woman, yet her gentle nature has made her a target for relentless suffering. Ever since the arrival of Lily—referred to as her sister-in-law—Charlotte has endured cruel slander and malicious defamation that have deeply wounded her. Seeing the unjust torment inflicted upon the very person who saved him ignites a fierce resolve within the protagonist. Having once been helpless in the face of death, he now vows to use his newfound existence to protect her. It is his turn to save Charlotte, and he will stop at nothing to exact satisfying retribution against those who dare to harm her.